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Time-resolved areal-density measurements with proton spectroscopy in spherical implosions
V A Smalyuk1, P B Radha, J A Delettrez
1Laboratory for Laser Energetics, University of Rochester, 250 East River Road Rochester, New York 14623, USA.
Physical Review Letters
|April 12, 2003
Summary
Researchers measured the areal density of direct-drive spherical targets using proton spectroscopy. The target areal density reached 123+/-16 mg/cm(2) at peak compression.
Area of Science:
- Nuclear Fusion
- Plasma Physics
- High-Energy-Density Physics
Background:
- Direct-drive spherical target implosions are crucial for inertial confinement fusion research.
- Understanding target areal density evolution is key to achieving fusion conditions.
Purpose of the Study:
- To infer the temporal history of target areal density during direct-drive spherical implosions.
- To measure peak areal density achieved in OMEGA laser system experiments.
Main Methods:
- Utilized 14.7-MeV deuterium-helium-3 (D3He) proton spectroscopy.
- Employed the 60-beam, 30-kJ UV OMEGA laser system for implosions.
- Analyzed implosions of plastic CH capsules filled with D3He fuel.
Main Results:
- Inferred target areal density growth by a factor of approximately 8 during neutron production (approx. 400 ps).
- Measured a peak areal density of 123+/-16 mg/cm(2) at peak compression.
- Characterized the implosion of a 950-micrometer-diameter, 20-micrometer-thick CH capsule.
Conclusions:
- Proton spectroscopy provides a valuable tool for diagnosing target areal density in fusion implosions.
- The study demonstrates significant areal density increase leading up to peak compression.
- Achieved high areal density is a critical step towards controlled fusion energy.
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